If you happen to go to Great Clips (or have one near you), I've had amazing results with this detangler: GreatClips.com - Kids Solutions by Great Clips - Afraid Knot Detangler
I'm not sure what it is (maybe it's the sunflower oil, I don't know) but something about it grew and strengthened Lacey's forelock like crazy. I'd braid it and leave it braided for a week after spraying this stuff and when I unbraided it, her forelock would be visually longer.
Lacey literally used to just have a puff of hair between her ears and now it's passing her eyes (and it's really strong and gorgeous)!
I didn't like what it did to her tail though so I just use it as a forelock spray but that's alright.
For tails, I've had great luck with shampooing+conditioning (let sit at least 10 minutes before rinsing, human conditioner only) on a monthly basis, then using Cowboy Magic detangler (never use silicone based detanglers like ShowSheen, they'll just dry out the hair and cause it to break), braid the tail from the tailbone down and bag it if you want. Then just unbag+unbraid once a week, use more Cowboy Magic detangler, brush out the tail, and put it up again.
I do that routine to her tail all winter and by the spring, her tail usually has nearly doubled in thickness. I leave her tail down and out all summer for fly protection and prettiness (cuz what's the point of cultivating a pretty tail if you never see it!) but because of the care I take of it all winter, it's not generally too damaged by the end of summer.
Another thing I do is I never ever do anything to her mane, tail, or forelock with detangler. So much damage can happen through one time of "Oh, I don't want to this time".
I also trim about an inch off all her hair once a month (after her tail bath) just to keep the ends healthy and perky.
Hopefully this was marginally helpful and not too much information! :)